All active plugins not showing up

Everything has been running fine, but all of a sudden after installing/activating (and then promptly deactivating/uninstalling) two new plugins, my list of plugins isn’t showing up correctly. It says there are 15 total plugins installed, 13 active, but only one is actually showing up in the list (Better WP Security). All of the other active plugins are apparently still there and functioning, they’re just not showing up in the list. It’s not a browser cache issue because I logged in from a different browser and saw the same thing.

Any ideas what’s going on? Is there any way to force WP to refresh the list of plugins installed and active?

UPDATE: This is really strange. Looking at the browser source HTML for that page in the admin, it looks like the entire page isn’t loading. The HTML code just stops after that first plugin listing. No closing body, html or any other tags. I tried replacing plugins.php from a fresh download of WP with no change.